Ansonia hanitschi | Ansonia longidigita
Ansonia malayana | Ansonia minuta
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Ansonia malayana from: http://amphibia.my/
The genus Ansonia Stoliczka has been distinguished from Bufo on the basis of larval and adult morphological characters, some of which are clearly related to the profound ecological differences between these genera (Inger, 1954). Conspicuous among these diagnostic and adaptive characters of Ansonia are: membranous webbing; slender body and long legs; streamlining of tadpoles; sucker- type oral disk of tadpoles; and relatively large and pigmentless ova. These modifications adapt Ansonia to a life in and along swift, rocky streams. Weak subarticular tubercles and lack of parotoid glands also distinguish Ansonia from Bufo, though they do not seem to be part of the adaptive complex.
Dr. Joseph Tihen, University of Notre Dame, has examined most of the species of Ansonia included in this paper in connection with his own studies on Bufonidae and has called attention to several other differences between Ansonia and Bufo (Tihen, 1960) . Most of the species of Ansonia have very long tensor fasciae latae, whereas in Bufo this muscle is short. The quadratojugal, which in Bufo always touches the maxilla, is reduced in Ansonia and rarely reaches the maxilla. Finally, a well-developed sharp ridge crosses the posterior portion of the parasphenoid in Ansonia but is absent in Bufo.
The tadpoles of Ansonia differ radically from those of Pedostibes Gunther and Pelophryne Barbour, the other abundant genera of Malaysian bufonids. The tadpole of Pedostibes has the subspherical body form and non-specialized oral disk of Bufo larvae. Larval Pelophryne, however, are extremely specialized for rapid development in very small pools of rain water; they apparently subsist during the entire larval period on yolk, have a degenerate oral disk, and lack a spiracle (Inger, 1960).
Adult Pelophryne differ from Ansonia in having the coccyx fused to the sacrum (movable joint in Ansonia) and provided with a broad, horizontal, flattened plate (coccyx laterally compressed in Ansonia).
In addition, the hands and feet of Pelophryne have a peculiarly thickened web. Adult Pedostibes differ from Ansonia in the possession of distinctly webbed outer fingers, dilated finger tips, well-developed subarticular tubercles, and parotoid glands. Pedostibes has marked arboreal tendencies.
Ansonia malayana Inger, 1960
Type locality: "4,000 feet in the Larut Hills, Perak, Malaya", Malaysia.
Holotype: BM 1900.9.26.16.
Ansonia longidigita Inger, 1960
Type locality: "4,200 feet on Mount Kina Balu, North Borneo", Malaysia (Borneo).
Holotype: BM 18.104.22.168.
Ansonia hanitschi Inger, 1960
Type locality: "Kadamaian River at 4,200 feet on Mount Kina Balu, North Borneo", Malaysia (Borneo).
Holotype: BM 22.214.171.124.
Ansonia platysoma Inger, 1960
Type locality: "Luidan River near Bundu Tuhan at 3,300 feet on Mount Kina Balu, North Borneo", Sarawak, Malaysia.
Holotype: FMNH 28213.
Ansonia albomaculata Inger, 1960
Type locality: "1,400-2,000 feet above sea level, in the headwaters of the Baleh River, Third Division, Sarawak", Malaysia (Borneo).
Holotype: FMNH 81975.
Ansonia minuta Inger, 1960
Type locality: "in primary forest at 450 feet above sea level at Matang, First Division, Sarawak", Malaysia (Borneo).
Holotype: FMNH 77424.
Inger, R.F. 1960. A review of the Oriental toads of the genus Ansonia Stoliczka. Fieldiana: Zoology: 473-503.